Means permitting limited retrograde movement of strip stock on retraction of feed means



Feb. 25, 1958 c. P. MICHLEIN 2,324,316

MEANS PERMITTING LIMITED RETROGRADE, MOVEMENT OF STRIP STOCK ONRETRACTION OF FEED MEANS 2 Sheets-Sheet 1 Filed Sept. 8, 1954 INVENTORACarl PMicizZem BY ATTORNEYS Feb. 25, 1958 c. P. MICHLEIN 2,824,316 MEANSPERMITTING LIMITED RETROGRADE, MOVEMENT OF STRIP STOCK ON RETRACTION OFFEED MEANS 2 Sheets-Sheet 2 Filed Sept. 8, 1954 m m m w MA P MW 6 UnitedStates Patent MEANS PERMITTING LIIVIITED RETROGRADE MOVEMENT OF STRIPSTOCK ON RETRAC- TION OF FEED MEANS Carl P. Miclilein, Shelton, Conn.,assignor to The Shelton Tack Company, Shelton, Conn., a corporation ofConnecticut Application September 8, 1954, Serial No. 454,813

7 6 Claims. (Cl. 10-178) I This invention relates to apparatus forlongitudinally advancing or feeding flat bar or strip stock, and moreparticularly to. strip-feeding apparatus used in conjunction with amachine which is adapted to fabricate articles from the strip..

The invention is illustrated and described in connection with the makingof carpet tacks; however, it should be understood that such disclosureis for illustrative purposes and that the invention is not limited tothe specific machine shown since it has utility generally in the fieldof strip feeding.

Heretofore, inthe manufacture of carpet tacks by automatic machinery,the strip stock from which blanks or slugs were cut was not taken from acontinuous supply or coil but instead was fed to the machine in the formof long, straight strips of determinate length.

This procedure necessitated considerable attention being given by theoperator to each machine, since it was necessary at brief intervals toreplenish the supply to the machines with new strips of stock.

This disadvantage is obviated by the present invention, and an object ofthe invention is to provide an improved and simplified means for feedingstrip stock to a tack machine from a continuous coil which contains avery.

great length of the stock. 7

Another object of the invention is to provide an improved apparatus forintermittently feeding strip from a continuous coil or supply of thestock.

A still further object of the invention is to provide animproved'strip-feeding apparatus in accordance with the foregoing, whichis simple in construction with relatively few parts, is small andcompact, reliable and foolproof in its operation and economical toproduce.

A feature of the invention resides in the provision of an improvedstrip-feeding apparatus as above set forth, wherein the operating partsand components are readily accessible for inspection or servicing.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is a side elevational view of a tack machine and improved stripfeed made in accordance with the invention.

' Fig. 2 is a perspective view of a continuous coil of strip stock,carried by a supporting means which enables the strip to be fedcontinuously from the coil.

Fig. 3 is a transverse vertical section taken on line 3--3 of Fig. 1.

Fig. 4 is atransverse vertical section taken on line 4-4 of Fig. 1.

Fig. 5 is an axial sectional view of the feed head of the apparatus.

Fig. 6 is a left end view of the feed head shown in Fig. 5.

Fig. 7 is a transverse sectional view taken on line .7-7 of Fig. 5.

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Fig. 9 is a perspective view of a sliding collar employed in theconstruction of Fig. 5.

Fig. 10 is a perspective view of a guide and support arm included in thestructure of Fig. 5.

Fig. 11 is a view like Fig. 5 but showing a modification of theinvention.

Referring to Fig. 1, a tack machine is shown comprising a base 20supporting a machine frame 21 which has uprights 22 provided withbearings 23, the latter carrying a main crank or carn shaft 24. Theshaft 24 operates a ram 25 having shearing tools or bits 26 cooperablewith a bed knife 27 for cutting slugs from strip stock fed to themachine. Cooperable with the shearing tools 26 is a clearer bar 28 whichholds the cutoff slugs against one of the tools 26 as the latter descendpast the bed knife 27.

Adjacent the shearing tools 26 is a guide or stop 29 adapted to beengaged by the advancing end of the strip stock 30 which is fed to themachine.

In accordance with the present invention a novel and improved apparatusis provided in conjunction with the tack machine by which continuousstrip stock may be fed thereto from a continuous coil or supply.Referring to Fig. 2, the strip 30 is shown as being supplied in a coil31 which is mounted on a holder 32 adapted to feed the strip from thecoil. The improved strip-feeding apparatus of my invention is arrangedto receive the continuous strip 30 from the coil 31 and tointermittently feed the strip into the tack machine.

Referring again to Fig. 1 the improved feeding apparatus comprises anelongate guide barrel 33 through which the strip 30 may pass, with acertain amount of clearance. The guide barrel 33 carries asemi-spherical knuckle or bearing member 34 which is held in astationary socket 35 mounted on a post 36, the latter in turn beingcarried by an arm 37 secured to the base 20 of the machine.

The arm 37 also carries a depending bracket 38 mounting a shaft 39 whichhas oppositely-extended arms 40 connected by flexible straps 41 to thebarrel 33. The straps 41 wrap around the barrel 33 in oppositedirections, whereby oscillation of the shaft 39 will cause correspondingoscillation of the barrel 33. One of thearms 40 has connected to it adepending drive arm 42 actuated by a link 43 which is reciprocated bysuitable mechanism (not shown) in the tack machine.

The guide barrel 33 slidably carries a collar bearing 44 held by springs45 in a guide fork 46 mounted on the supporting arm 37 of the apparatus.

Referring to Fig. 5, the guide barrel 33 at its lower end has disposedwithin it a bushing 47 carrying a guide member 48 in the form of a dischaving an elongate central opening or slot 49 through which the strip 30passes.

Referring to Figs. 7 and 8, the lower end portion of the guide barrel 33has secured to its side a bar 50 constituting a longitudinally-extendingrib, and attached to the rib 5.0 is a guide and support arm 51, Figs. 5,7 and 10, having a laterally-extended extremity 52 provided with a slit53 through which the strip 30 extends.

Slidably mounted on the lower end of the guide barrel 33 is a collar 54having a longitudinal slot 55 in it, said slot providing clearance forthe rib 50. The collar 54 carries a gripper means comprising a stripsupporting member '56 and a bearing member 57, the latter pivotallycarrying an angularly disposed clamping arm 58 mounted by a screw 59 andurged by a helical compression spring 60 into engagement with the strip30, saidstrip being thereby maintained in engagement with a surface 61of the support member 56. The gripper means thus provided has aunidirectional action, gripping the strip 30 and feeding the strip fromright-to-left in response to like movement of the collar 54, andenabling the collar and 3 gripper to move from left-to-right withoutmovement of the strip 30.

The collar 54 is connected by links 62 to a second collar 63 slidablycarried on the guide barrel 33, thecollar 63 having an annular groove 64accommodating pins 65, Fig. 4, carried by arms 66 secured to a shaft 67which is turnable in a bearing bracket 68 carried by the fork member 46.The shaft 67. has a depending operating arm 69 connected through ayieldable driving connection 70 to a link 71 which is reciprocated by abell crank 72. actuated by a cam shoe 73 on the shaft 24 of the machine.Adjustment of the stroke of the bell crank 72 is effected by anadjusting screw 74 carried by the machine. By the above construction itwill be seen that reciprocation of the gripper members 56 and 57 iseffected in response to turning of the shaft 24.

Referring again to Fig. 1, the guide and support arm 51 is so arrangedand organized as to rest on the bed knife 27, thereby supporting thelower portion of the guide barrel 33 and the gripper means carriedthereby during the operation of the feeding apparatus.

Operation of the apparatus as described above, is as follows:

Turning of the shaft 24 will reciprocate the ram 25 of the tack machine,lowering and raising the shearing tools 26 and enabling them to shearoff end portions of the strip stock in conjunction with the bed knife27. The stock 30 is sheared off at an angle which differs slightly from90 degrees relative to the length of the strip.

Turning of the shaft 24 oscillates the bell crank 72 and reciprocatesthe gripper members 56, 57 and the collars 54 and 63. This will causeintermittent feeding or advancing of the strip 30 toward the tackmachine. An overfeed is provided by the cam 73, and as the foremost endof the strip 30 engages the guide 29 it will be halted, the rest of thefeeding movement of the bell crank and link 71 being absorbed by theyieldable spring connection 70.

At the same time that the gripper members are reciprocating, the guidebarrel 33 is caused to turn or oscillate through an arc of 180 degreesby virtue of reciprocation of the drive link 43. This will cause theopposite sides of the strip stock 30 to be alternately presented to theshearing tools 26, and by such arrangement the cutoff slugs will be madeto have a wedge shape which is of importance in the formation of carpettacks and the like.

Oscillation of the guide barrel 33 and gripper means about the axis ofthe barrel will cause a twisting of the strip 30 within the barrel. Withthe supply coil 31 placed in a horizontal plane as shown in Fig. 2, thestrip 30 will extend in a vertical plane and be twisted in oppositedirections through arcs of 90 degrees, thereby being fed substantiallyhorizontally to the shearing tools 26.

During the oscillation of the gripper means 56, 57 about the axis of theguide barrel 33, the support arm 51 will also oscillatebut will remainin contact with the bed knife 27, providing a support for the lowerportion of the guide barrel and for the gripper means, and insuring thatthe strip 30 will be positioned against the top surface of the bed knife27.

I have found that the twisting of the strip 30 within the guide barrel33 provides a desirable, yieldable gripping action in conjunction withthe guide 48. By properly proportioning the diameter of the guide barrel33 with re spect to the width of the strip 30, the twisting forceexisting at the guide 48 will permit a slight retrograde movement of thestrip 30 but will prevent any appreciable retrograde movement fromoccurring. This is highly desirable, since it provides a clearancebetween the foremost end of the strip 30 and the shearing tools 26 andguide 29 during the return stroke of the tools, yet the strip 30 is heldsufficiently to enable the gripper members 56 and 57 to retract withoutpulling back the strip. Thus the clampmg arm 58 is enabled to take a newbite into the strip.

4 The guide 48 thus constitutes in effect a back check, in conjunctionwith the twisting action of the strip 30, and this is an importantfeature of the present invention.

A modification of the invention is shown in Fig. 11, and components inthis figure which are similar to those already described above have beengiven like characters. The ditference between the construction of Fig. 5and Fig. 11 resides in the strip guide and back-check means. In Fig. 5,the guide and back check comprises a single member 48 having an elongateslot through which the strip 30 passes. In Fig. 11 a spring-charged backcheck 75 is provided, secured to the bushing 47, the back check 75comprising a support member 76, a bearing member 77, a pivoted clamp arm78 and a retainer screw 79, the latter carrying a compression spring 80normally urging the clamping arm 78 clockwise or to the right as viewedin Fig. 11.

The clamping arm 78 is arranged to enable a slight amount of retrogrademovement of the strip 30 to be had in response to left-to-right movementof the gripper members 56 and 57. This provides the clearance for theshearing tools 26. The back check 75 prevents appreciable retrogrademovement of the strip 30, however, thereby enabling the gripper means56, 57 to get a new bite each time it is reciprocated, thus effecting areliable intermittent advance or feed of the strip 30 without binding ofthe shearing tools.

Variations and modifications may be made within the scope of the claimsand portions of the improvements may be used without others.

I claim:

1. Means for feeding a continuous supply of flat strip from a reelcomprising a guide having an opening through which the strip can passand advance; means mounting the guide for turning movement about saidopening, said guide comprising support means positioned on one side ofthe strip and a bearing means diametrically opposite the support todefine therebetween a slot slidingly engageable with opposite sides ofthe strip and imparting to said strip a twisting movement in oppositedirections about its length; a unidirectional-acting gripper meanscooperating with said guide and engageable with said strip for grippingthe same, said gripper means being axially movable relative to saidguide opening to impart longitudinal advancing movement to the strip andbeing keyed to the guide against relative turning; said guide beingformed to provide a barrel portion on the side of the slot opposite thegripper means and having a diameter determinately larger than the widthof the strip; and baclccheck means including a pivotally mounted clamparm opposite and extending towards the support means; and adjustablespring means biasing the arm towards the barrel portion with sufficienttension to enable a slight retrograde movement of the strip prior tolocking of the strip by the clamp arm, whereby the strip when beingtwisted from one side to the other is permitted to buckle within thebarrel a determinate amount to cause a slight retrograde movementthereof which provides a clearance for the foremost end of the strip andthe back-check means enables the movement but prevents appreciableretrograde movement.

2. The invention as defined in claim 1 in which there is a second guidefor the strip, fixedly secured to the firstmentioned guide and engagingthe strip at a point remote from the first-mentioned guide; and meansproviding a supporting surface, said second guide resting on saidsurface and supporting the first-mentioned guide and gripper meansthereby.

3. The invention as definedin claim 1 in which the gripper meanscomprises a pair of arms extending beyond said guide and spaced fromsaid guide opening, one of said arms forming a support, and a pivotedangularlydisposed pawl arm connected to said other arm biased towardsaid support, said pawl arm being adapted to clamp the strip against thesupport.

4. The combination of a supply coil of flat strip stock; means forsupporting said coil, to enable the strip to be fed therefrom; a guideincluding a support means positioned on one side of the strip andbearing means diametrically opposite the support to define therebetweena narrow slot through which the strip extends, said slot closely,slidably confining the strip; means mounting the guide for turningmovement about said slot, said guide imparting turning movement to thestrip about its length when the guide is turned; a unidirectional-actinggripper means carried by the guide and gripping said strip, said grippermeans being movable on said guide axially of the slot therein andimparting longitudinal advancing movement to the strip when so moved,and said gripper means being keyed to the guide against relativeturning; a guide barrel rigidly connected to the guide and enclosing andsupporting the strip in a zone between the guide and supply coil, saidbarrel closely confining the strip and being determinately larger thanthe strip to permit a controlled amount of buckling of the striptherein; and back-check means including a pivotally mounted clamp armopposite and extending towards the support means; and adjustable springmeans biasing the arm towards the barrel portion with sufiicient tensionto enable a slight retrograde movement of the strip prior to locking thestrip, whereby the strip when being turned from one side to the other ispermitted to buckle within the barrel a determinate amount to cause aslight retrograde movement thereof which provides a clearance for theforemost end of the strip and the back-check means enables the slightmovement but prevents appreciable retrograde movement.

5. Means for feeding a continuous supply of flat strip comprising aguide having an opening through which the strip can pass and advance;means mounting the guide for turning movement about said opening, saidguide having portions slidingly engageable with opposite sides of thestrip and imparting to said strip a twisting movement in oppositedirections about its length; a unidirectional-acting gripper meanscooperating with said guide and engageable with said strip for grippingthe same, said gripper means being axially movable relative to saidguide opening to impart longitudinal advancing movement to the strip andbeing keyed to the guide against relative turning; said portions of theguide providing a desirable, yielding, gripping action during twistingof the strip whereby the twisting force existing at the guide allows aslight retrograde movement of the strip to provide a clearance for theforemost end of the strip, yet holding the strip sutficiently tight toenable the gripper means to retract without pulling back on the strip,thus constituting an effective back check; in which the gripper meanshas a collar extending around the guide and having a longitudinal slotin it; and in which the guide has a longitudinal rib occupying the saidslot, the rib and slot constituting keying means between the guide andgripper means.

6. The invention as defined in claim 5 in which there is a second guidefor the strip, fixedly secured to the firstmentioned guide and engagingthe strip at a point remote from the first-mentioned guide, said secondguide being attached to the said longitudinal rib.

References Cited in the file of this patent UNITED STATES PATENTS

